Web pick-up for two wire forming paper machine



April. 15, 1969 D. A. ELY, SR 3,433,852

WEB PICK-UP FOR TWO WIRE FORMING PAPER MACHINE Filed Oct. 28, 1965INVENTOR DONALD A. ELY SR.

AT TO RNEYS United States Patent U.S. Cl. 162-303 1 Claim The presentinvention relates to improvements in paper making machines and moreparticularly to an improved two wire machine and mechanism for handlingand dewatering the paper web.

In a two wire forming paper machine, stock is deposited into the formingzone between two traveling porous wires. An example of this type ofmachine is shown in U.S. Patent No. 2,821,120 issued to -R. J. Thomas etal.

The upper and lower wires of the two wire machine are each provided withdewatering means within their loops so that water is removed from theweb being formed through each of the wires eliminating the two sideseffect on the web which is experienced when a web is formed on a singlewire. At the end of the dewatering run between the wires and past couchrolls, the web is removed and transferred to the press section of thepaper making machine.

In accordance with the teachings of the art, the web was removed fromthe lower forming wire after it had made the turn past the couch roll.This was conventionally done by a pick off felt into a first press nip.The press nip is formed between the press roll couple usually having aplain press roll and a water receiving roll. It is necessary that thefelt engage the water receiving roll to prevent marking and otherwisedamaging the paper web and in the press nip the water is forced from theweb through the felt into the water receiving roll. It has also beennecessary that the web be on the upper surface of the felt in the firstpress nip so that the water is removed in a downward direction and sothat the web follows the felt and is not wrapped around the plain rolland not be carried by the felt.

In order to accomplish the necessary support of the web on a felt with afelt between the web and a water receiving roll, it has been necessaryto use a second felt, bringing it up below the web to sandwich the webor to turn the web and felt so that the web is on top of the felt. Eachof these methods incur disadvantages, requiring extra equipment andextra space in the press section of a paper machine.

It is accordingly an objective of the present invention to provide animproved two wire forming machine which avoids the disadvantagesheretofore encountered in the web transfer to the press section.

It is a further object of the invention to provide an improved two wireforming with a web transferring mechanism which avoids the necessity ofproviding a second felt to support the undersurface of a web and passbetween the web and the water receiving roll of the first press couple.

It is a further object of the invention to provide an improved two wireforming mechanism and mechanism for transferring the web to the presssection which avoids the necessity of turning the web and felt to bringthe web on the upper side of the felt and the additional space requiredby such structure with the attendant disadvantages of having to hold theweb on the felt against centrifugal force.

A feature of the invention is the provision of a two wire formingmechanism having an upper and lower forming wire wherein the formed webis picked off the upper wire past the couch roll by pick off felt andcarried on the upper surface of the felt into a press couple with a.water receiving roll below the felt.

Patented Apr. 15, 1969 ice Other objects, advantages and features willbecome more apparent with the teaching of the principles of the presentinvention in connection with the disclosure of the preferred embodimentthereof in the specification, claims and drawings, in which:

The drawing is a front elevational view shown in schematic form of aportion of a paper making machine embodying the principles of thepresent invention.

As shown on the drawing, a two wire forming mechanism includes an upperlooped forming wire 10 and a lower looped forming wire 11. The formingwires are supported so that they come together to provide a forming zoneF for the stock, followed by a dewatering run D.

The paper stock is delivered to the form-ing zone F from a slice nozzle12 connected to a suitable headbox structure and preferably the stock isdelivered under pressure through the nozzle 12 into the forming zone F.

Suitable supporting rolls such as 13 and 14 are provided for the upperwire and similar supporting rolls, g-uide rolls and tensioning rollssuch as 16 and 17 are provided for the lower vwire 11. At the end of thedewatering run D are couch rolls 15 and 18 within the upper and lowerwires 10 and 11.

Also within the upper and lower wires 10 and 11 at the forming zone Fare upper and lower dewatering devices 19 and 20. These may be suctionrolls or suction boxes or other suitable mechanism and is shaped toguide the wires into the forming zone F and arranged to accommodate andaid the flow of water from the pulp to begin the formation of the web asthe wires converge and taper together into their dewatering nun. Furtheralong the run are additional dewatering means 21 and 22, such as in theform of foils or slices, table rolls and suction boxes.

The upper couch roll 15 is provided with a suction gland 15a whichcauses the web to follow the upper wire at the end of the dewatering runand be carried up on the upper forming wire.

The web is removed from the upper forming wire following the couch roll15 by pick off felt 23. This felt is guided into a pick ofi relationshipwith the upper Wire 10 by a suction roll 24 having a suction roll gland24a therein. The web then follows along on the upper surface of the felt23. The felt is provided with additional guide rolls and a feltdewatering mechanism such as will be fully appreciated by those versedin the art.

The web W being carried on the upper surface of the felt 23 passes intoa nip formed between a press roll couple having rolls 25 and 26. Theupper roll 25 is preferably a plain press roll and the lower roll 26 isa water receiving roll. In a preferred form, the lower roll 26 is agrooved roll such as the type disclosed and claimed in U.S. Patent No.3,198,693 issued to E. J. Justus.

Thus, the web W carried on top of the felt 23 engages the upper plainroll 25 while it has the felt between it and the grooves of the waterreceiving roll 26. The water is pressed through the felt into the waterreceiving roll 26 which is provided with a suitable water removing meansas shown schematically at 27.

Thus, it will be seen that I have provided an improved two wire formingmechanism with a web transfer arrangement that meets the objectives andprovides the advantages above set forth. The disadvantages of the priorart structures which require taking the web off the lower wire and thenecessity of handling it by special means so that the web will be on topof the felt are avoided. The structure offers a saving in space anddirect handling of the web on the upper surface of the felt and obtainsadvantages above set forth.

it will be understood that modifications and variations may be effectedwithout departing from the scope of the novel concepts of the presentinvention.

3 4 I claim as my invention: roll having a suction gland facing theupper wire and 1. A two wire forming paper machine comprising in forminga pick off nip with the upper wire, and combination, a press roll couplein nip defining relation with the felt upper and lower forming wiresdefining a horizontal passing horizontally therebetween having a lowerweb forming run between them, 5 water receiving roll engaging the feltso that the Web a pulp delivering means at the forming end of the Wiresis carried on the upper surface of the felt and enfor placing a layer ofstock between the wires to form gages the upper roll of the presscouple. a web, dewatering means within each of said wires for removingwater from the web through each of References Cited the Wires, th e 1 d,c uch on he 10 UNITED STATES PATENTS means suppor lng e wir s me u mg 0r s a end of the dewatering run of the Wires, fi i"" said couch roll forsaid upper wire having a suction 3198693 8/1965 omas e a H gland whichcauses the web to follow the upper Wire Justus 162 272 upwardly in agenerally vertical Plane 15 DONALL H. SYLVESTER, Primary Examiner.

a pick ofI" felt in an angular web pick off relation with the generallyvertical plane of the upper wire beyond ALBERT HODGSON AssistantExaminerand above the upper wire couch roll, US. Cl. X.R. a suction pickoil roll within the felt above the couch 162203, 272

1. A TWO WIRE FORMING PAPER MACHINE COMPRISING IN COMBINATION, UPPER ANDLOWER FORMING WIRES DEFINING A HORIZONTAL WEB FORMING RUN BETWEEN THEM,A PULP DELIVERING MEANS AT THE FORMING END OF THE WIRES FOR PLACING ALAYER OF STOCK BETWEEN THE WIRES TO FORM A WEB, DEWATERING MEANSWITHINEACH OF SAID WIRES FOR REMOVING WATE FROM THE WEB THROUGH EACH OFTHE WIRES, MEANS SUPPORTING THE WIRES INCLUDING COUCH ROLLS AT THE ENDOF THE DEWATERING RUN OF THE WIRES, SAID COUCH ROLL FOR SAID UPPER WIREHAVING A SUCTION GLAND WHICH CAUSES THE WEB TO FOLLOW THE UPPER WIREUPWARDLY IN A GENERALLY VERTICAL PLANE, A PICK OFF FELT IN AN ANNULARWEB PICK OFF RELATION WITH THE GENERALLY VERTICAL PLANE OF THE UPPERWIRE BEYOND AND ABOVE THE UPPER WIRE COUCH ROLL, A SUCTION PICK OFF ROLLWITHIN THE FELT ABOVE THE COURCH ROLL HAVING A SUCTION GLAND FACING THEUPPER WIRE AND FORMING A PICK OFF NIP WITH THE UPPER WIRE, AND A PRESSSROLL COUPLE IN NIP DEFINING RELATION WITH THE FELT PASSING HORIZONTALLYTHEREBETWEEN HAVING A LOWER WATER RECEIVING ROLL ENGAGING THE FELT SOTHAT THE WEB IS CARRIED ON THE UPPER SURFACE OF THE FELT AND ENGAGES THEUPPER ROLL OF TH PRESS COUPLE.